A porous Zn-based metal-organic framework with an expanded tricarboxylic acid ligand for effective CO 2 capture and CO 2 /CH 4 separation

A trigonal nanosized carboxylate ligand, 4, 4′,4″-(triazine-2,4,6-triyl-tris(benzene-4,1-diyl))tribenzoic acid (H3TAPB), has been applied in the construction of a highly porous metal−organic framework (MOF). A solvothermal reaction of H3TAPB and a zinc salt in a mixed solvent of DEF/dioxane/H2O produces the targeted porous MOF [Zn3(TAPB)2(H2O)2](DEF)4(H2O)3 (1, DEF = N,N-Diethylformamide). This MOF contains a linear Zn3 secondary building unit with two terminal water molecules occupied the axis positions, which is connected by the TAPB3− ligands to afford a 3-fold interpenetrated framework with a large calculated void volume (69.7%). The activated MOF shows exceptional porosities and high CO2 uptake capacities as well as good sorption selectivity of CO2/CH4 around room temperature.